Bitcoin prices continued to tumble Thursday after one of China's biggest exchanges said it would stop trading the cryptocurrency later this month amid an impending crackdown directed by the country's central bank.

Bitcoin prices on London's bitsmap exchange tanked 10.75% from Wednesday's close to $3,450 each by 9 a.m. ET, the lowest since Aug 10. Bitcoin prices have fallen nearly 30%, or more than $1,400 from the all-time peak the virtual currency reached on Sept. 1.

Federal Reserve Chairman Jerome Powell said in a webcast discussion in Switzerland that Facebook's proposed digital currency would probably have so many users that it might cause instability in the financial system.

Manpower Group is seeing significant un-reflected value from past performance, glowing future prospects for the coming three to five years, and a future currency-related rise due to an eventual weakening of the dollar.